What it looks like
A yellow diamond-shaped warning sign with a black legend reading LOW SHOULDER.
When you'll see it
Where the shoulder drops below the level of the travel lane, often on rural highways or roads awaiting shoulder repair.
What to do
Stay on the roadway and avoid drifting onto the shoulder; if a wheel drops off the edge, ease off the gas and steer back gradually.
Source: Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition — FHWA.
